The use of SAR satellite imagery to measure active layer moisture contents in Arctic Alaska

Abstract

Synthetic aperture radar (SAR) has the potential for measuring near surface soil moisture contents for very large areas. The polar orbiting European Remote Sensing satellite (ERS-1) of the European Space Agency (ESA) has onboard an active C-band SAR sensor. We have analyzed SAR imagery over a small research watershed, Imnavait Creek, located in the northern foothills of the Brooks Range in Alaska, U.S.A. This watershed is treeless and completely underlain with permafrost. After geometrically and radiometrically correcting each pixel (25 m by 25 m) in the image, corrected pixel values were correlated with corresponding field moisture contents measured along transects in the watershed for two passes of the satellite. Coefficients of determination, r2, between the corrected pixel value and measured moisture content were 0.49 on June 12, 1993 and 0.53 on August 2, 1993; with the data sets combined the value was 0.50.